The present invention relates to a mine door operating system usable with two or more mine doors such as in an airlock arrangement.
Doors used in mines operate under conditions not usually encountered by typical doors. Mine doors have door leafs that tend to be heavy and dimensionally large and are thus subject to large forces due at least in part to air flow in the mine and consequent air pressure differentials on opposite sides of a door. A leaf can be as large as 10 feet wide and 20 feet high and sometimes even larger and weigh more than a thousand pounds when designed for pressure differentials of seven inches of water gauge and over two thousand pounds for a pressure differential of 20 inches of water gauge. The leafs can thus be subject to large forces from the air pressure differential on opposite sides of the leafs. Even a small pressure differential can create large forces on the large leafs making it difficult to control their movement during opening and closing and difficult to start opening movement and complete closing. Further, leafs need to be positively driven particularly in the closing direction to prevent door runaway and impact when the leafs reach the end of their closing movement, particularly when the closing movement is toward the low pressure end of the mine, the normal condition. Continued impact and runaway would cause damage and premature wear to the leaf drive, leaf and door frame.
Additionally, to reduce the risk of damage and to improve safety, it would be desirable to simply and reliably lock the leafs in both the open and closed positions and at any position in-between should there be a power outage or in the event the leaf encounters an obstruction during movement. It would also be desirable to be able to manually override the locked condition of any leaf.
Air locks are provided in mines to allow vehicles and personnel to pass thru mine passageways while controlling air flow between passageways or through a passageway and/or for fire prevention and control. Air locks use at least two doors of the above described type, a mine side or return air side door and a mine entrance or fresh air side door. In some mines, e.g., coal mines, air locks are mandatory under government regulations. In an air lock, at least two doors are spaced apart along a mine passageway with one door being located at the mine end of the air lock and the other door being located at the entrance side (in some cases this side is referred to as the fresh air side and is upstream relative to normal air flow) of the air lock. FIG. 11 illustrates, in simplified form, a coal mine. The mine includes an air intake passageway (AIP) with an air inlet opening (AI) connected to a mine face passageway (MFP) to provide fresh air to the mine face. In normal operation, fresh air flows to the mine face thru the intake passageway. An air outlet opening (AO) is connected to the mine face via a air exit passageway (AEP). Air flowing across the mine face from the air intake is discharged through the air outlet. A neutral passageway (NP) connects the mine face to the exterior of the mine and is commonly in parallel to the air intake passageway and the air exit passageway. The neutral passageway provides for normal passage of personnel, machinery and mined material between the mine face and the mine exterior. In some locations in a mine, e.g., the air intake passageway AIP the doors of an airlock, AL, will all be considered to be fresh air (designated FA) side doors even though one of the doors is more adjacent the mine face than another door. All doors of an airlock AL may also be considered to be return air (RA) side doors even though one door is more adjacent the exit than another door, e.g., in an air exit passageway AEP, as defined by regulatory authorities. The neutral passageway has an airlock AL. The airlock in a neutral passageway is considered to have all doors in fresh air. Airflow, for normal operation is from the entrance, high pressure side of the mine, the air intake to the air outlet, the low pressure side of the mine. The pressure differential and flow rate in a neutral passageway are low relative to those in air intake passageways and air outlet passageways. In normal operation, one door of an air lock remains closed while the other door is open to allow movement into or out of the air lock while preventing air flow therethrough. Air lock doors need to be power operated for personnel convenience and to also manage movement of large leafs and the forces applied to the leafs due to the aforementioned pressure differentials. Since the normal air flow in a mine may reverse, the doors and leaf drives are preferably able to accommodate the reversal of force direction on the leafs and still properly operate. Also, the leafs are preferably positively held in the open and closed positions and in any position in-between where the leafs may be stopped.
Current leaf drive systems typically use a separate leaf drive for each door with each door utilizing a separate power source. The use of multiple power sources has been found to be desirable because the hydraulic piping is short which provides quicker response of the leaf drive and less play or give in the drive system. Such a system also utilizes two separate control systems each operating a respective door and requiring a separate housing for the power source and its control system. Further, when the doors are interlocked, the control system utilizes the interlock switches of one door to provide a signal that it is or is not permissible to open the leafs of the other door. The control systems are not interconnected providing an opportunity for the leafs of the multiple doors to malfunction since the controllers are not interconnected.
Leaf drive systems like those used with air locks, even though generally effective, do have drawbacks. They use power sources at separate locations, e.g., hydraulic pumps, each with their own control system also at separate locations. The separate control systems would need to be interfaced to effect proper and safe operation particularly with regard to interlocking so that one door cannot be opened unless the other door is closed. Another problem is having control circuit components on the mine side of the fresh air side door, i.e. in return air. When the second door is in return air, the air lock chamber is part of the return air side of the air lock and in some mine environments, like coal mines, will have to have sealed (explosion proof) components to eliminate ignition sources. Explosion proof as used herein means that a device such as a motor or component housing will not let ignited combustion products out of the device. Mine regulations as promulgated by MSHA (Mining Safety and Health Administration) refer to such equipment as xe2x80x9cpermissiblexe2x80x9d and regulate what will meet the standards of permissible. MSHA designates what equipment is permissible in particular environments. What is permissible or explosion proof will vary by the environment in which the equipment will be used. For example, what is permissible in a lead mine will not necessarily by permissible in a coal mine where methane may be present. If a combustible gas like acetylene is potentially present, equipment that is permissible for a methane environment may not be permissible in the acetylene environment. For environments where combustibles may be present, e.g., methane, meeting the requirements of xe2x80x9cpermissiblexe2x80x9d increases the cost of enclosures for control circuit components. Any motor powering, e.g., a motor driving a hydraulic pump needs to be explosion proof if it is positioned on the mine side of the fresh air side door, i.e. in return air, when in a mine environment possibly containing combustible gases like coal mines which can contain methane, as set forth in mining regulations. Also, the use of multiple pumps increases the cost of the leaf drive system and increases the fire hazard by having more potential ignition sources.
Another problem with the use of multiple door drive systems is the performance of maintenance work. A maintenance worker will lock out the equipment being worked on. However, if all the leaf drive systems in a multiple power source system are not locked out, there is a chance that the worker could be injured by a non-locked out leaf if that leaf moves while the worker is in the path of leaf movement.
There is thus a need for a simplified leaf drive system that provides effective and positive safe door operation in both the opening and closing directions of movement while reducing problems encountered with current door drive systems using multiple power sources while permitting the use of non-explosion proof (non-permissible, i.e., that which does not meet the standards of permissible) components.
Among the several objects and features of the present invention may be noted the provision of a drive system for multiple mine doors that utilizes a single source of power to open and close the mine door leafs; the provision of a door drive system that positively moves the leafs between open and closed positions; the provision of a door drive system that will positively maintain the leafs at any stopped position; the provision of a door drive system with an override to permit selective movement of leafs from a locked position; the provision of a door drive system that will positively maintain leafs in open and closed positions; the provision of a door drive system that prevents one door from opening while the other door is open or opening; the provision of a door operating system that can be safely utilized in a potentially explosive mine environment; the provision of a door operating system that reduces the number of potentially explosion causing components on the mine side of a fresh air side door of an air lock formed by the doors; the provision of a door operating system that is economical and effective in controlling leaf opening and closing; the provision of a door operating system that can be safely maintained; the provision of a door operating system that prevents leaf runaway; and the provision of a door operating system that will reduce the risk of fire and explosion in a mine.
In one aspect of the invention, a power operated mine door system forms an airlock space with a fresh air side on at least one side of the mine door system. The mine door system includes a plurality of doors mounted in a mine passage in spaced apart relation. Each door includes at least one leaf mounted for moving between open and closed positions. The doors form an airlock with an airlock space therebetween. At least one door is a return air side door and at least one door is a fresh air side door. A single source of pressurized fluid includes a non-explosion proof motor and a fluid pump driven by the motor. The motor is positioned in the mine passage on the fresh air side of the fresh air side door. A plurality of actuators are each operably connected to at least one leaf and to the single source of pressurized fluid to selectively apply a driving force to at least one leaf and thereby move the leaf between the open and closed positions. A control system is operably connected to the actuators for selectively allowing pressurized fluid to flow to the actuators for applying the driving force to a selected leaf for moving it to its open and closed positions.
The invention also involves the provision of a power operated mine door system installed in a mine passageway defining an airlock in the passageway separating a normally low pressure zone of the mine having a first air pressure and a normally high pressure zone of the mine having a second air pressure higher than said first air pressure. The system includes at least two doors installed in the passageway in spaced apart relation along the passageway forming an airlock and having an airlock space therein. The doors are operable to provide entry into and exit from the airlock space. The doors each include a pair of leafs movable between open and closed positions, one of the doors is located at a high pressure end of the airlock with its leafs being mounted for opening movement into the high pressure zone and another of the doors is located at a low pressure end of the airlock. A piston cylinder is operably connected to each of the leafs and is operable for moving at least one leaf between its open and closed positions. Each piston cylinder has a movable actuating element connected to a respective leaf for selectively exerting an opening force on the leaf to open it, a closing force on the leaf to close it and is operable to positively retain the leaf in its open and closed positions. A control system is operably connected to the piston cylinders for controlling the operation of the piston cylinders such that when one piston cylinder exerts an opening force to open the at least one leaf in one door, the at least one piston cylinder connected to the at least one leaf in the other door is operable to retain its at least one leaf closed whereby only one of said doors can have a leaf open at any given time. The control system is operable to selectively positively retain each said leaf in its closed position despite the different first and second air pressures. A fluid pump is positioned in the mine and operably connected to the piston cylinders for pumping pressurized fluid to and from the piston cylinders to power the piston cylinders to selectively open and close the leafs.
The present invention involves the provision a door system for a mine. The door system includes at least one leaf mounted for pivotal movement between open and closed positions. A power actuator is operably connected to the leaf and is operable to move the leaf between the open and closed positions. A power source is operably connected to the power actuator to provide pressurized fluid thereto to effect operation of the power actuator and thereby move the leaf between the open and closed positions. A control system is operably connected to the power source and the actuator to effect selective extension and retraction of the power actuator and to effect locking of the leaf in the open and closed positions and at positions therebetween.
An aspect of the present invention is the provision of a power operated mine door system forming an airlock space between a high pressure side and a low pressure side of the mine door system. The mine door system includes a plurality of doors mounted in a mine passage in spaced apart relation, each door including at least one leaf mounted for moving between open and closed positions. The doors form an airlock with an airlock space therebetween. A single source of pressurized fluid including at least one motor and at least one fluid pump driven by the motor, the source being positioned on one side of a door. A plurality of actuators are each operably connected to a respective leaf and to the single source of pressurized fluid to selectively apply a driving force to a respective leaf and thereby move the leaf between said open and closed positions and to selectively retain the respective leaf in its open position and closed position. A single electrical control system operably connected to the actuators and the source for selectively allowing pressurized fluid to flow to the actuators for applying said driving force to a selected leaf for moving it to its open and closed positions. The control system includes an interlock device including a sensor operably associated with each leaf to provide a signal that the respective leaf is closed and preventing opening of a leaf in one door if any leaf in another door is not closed.
The invention also involves the provision of a power operated mine door system forming an airlock space between a high pressure side and a low pressure side of the mine door system. The mine door system includes a plurality of doors mounted in a mine passage in spaced apart relation, each door including at least one leaf mounted for moving between open and closed positions, the doors forming an airlock with an airlock space therebetween. A source of pressurized fluid including at least one motor and at least one a fluid pump driven by a motor, the source being positioned on one side of one door. A plurality of actuators each operably connected to at least one leaf and to the source of pressurized fluid to selectively apply a driving force to at least one leaf and thereby move the leaf between said open and closed positions and to selectively retain the respective leaf in its open position and closed position. A single control system operably connected to the actuators and said source for selectively allowing pressurized fluid to flow to the actuators for applying the driving force to at least one leaf for moving it to at least one of its open and closed positions. The control system includes an interlock device including a sensor operably associated with each leaf to provide a signal that the respective leaf is closed and preventing opening of a leaf in one door if any leaf in another door is not closed. The single control system includes a signal receiving portion mounted in a single housing enclosing the signal receiving portion therein.
Another aspect of the invention involves a power operated mine door system forming an airlock space between a high pressure side and a low pressure side of the mine door system. The mine door system comprises a plurality of doors mounted in a mine passage in spaced apart relation, each door including at least one leaf mounted for moving between open and closed positions. The doors form an airlock with an airlock space therebetween. A source of pressurized fluid including at least one motor and at least one fluid pump driven by a said motor. The source is positioned on one side of a door. A plurality of actuators are each operably connected to at least one leaf and to the source of pressurized fluid to selectively apply a driving force to at least one leaf and thereby move the leaf between said open and closed positions and to selectively retain the at least one leaf in its open position and closed position. A single control system is operably connected to the actuators for selectively allowing pressurized fluid to flow to the actuators for applying driving force to a selected leaf for moving it to at least one of its open and closed positions. The control system includes an interlock device including a sensor operably associated with each leaf to provide a signal that the respective leaf is closed to prevent opening of a leaf in one door if any leaf in another door is not closed. The single control system includes a signal receiving portion mounted in a single housing enclosing the signal receiving portion therein.
Other objects and features will be in part apparent and in part pointed out hereinafter.